CN217034092U - Alternating voltage detection circuit for inhibiting temperature drift of photoelectric coupler - Google Patents
Alternating voltage detection circuit for inhibiting temperature drift of photoelectric coupler Download PDFInfo
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- CN217034092U CN217034092U CN202220140885.5U CN202220140885U CN217034092U CN 217034092 U CN217034092 U CN 217034092U CN 202220140885 U CN202220140885 U CN 202220140885U CN 217034092 U CN217034092 U CN 217034092U
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Abstract
The utility model discloses an alternating voltage detection circuit for inhibiting temperature drift of a photoelectric coupler, which comprises: the voltage division unit, the clamping unit and the controlled adjusting unit are arranged on the circuit board; the voltage division unit is used for controlling the on/off of the controlled regulation unit after voltage division; the output ends of the clamping unit and the controlled adjusting unit are respectively and electrically connected with the input positive electrode and the input negative electrode of the photoelectric coupler; the clamping unit provides working conduction voltage for the photoelectric coupler and plays a role in clamping protection; the photoelectric coupler periodically outputs pulse detection voltage from the output end under the control of the controlled regulating unit, so that the photoelectric coupler is prevented from working for a long time and working in a linear interval. The alternating voltage detection circuit solves the technical problem that in the prior art, the photoelectric coupler works for a long time and works in a linear interval, so that the temperature of an internal light emitter rises, the temperature drift phenomenon occurs, and the detection precision is reduced.
Description
Technical Field
The utility model relates to the technical field of electronic circuits, in particular to an alternating voltage detection circuit for inhibiting temperature drift of a photoelectric coupler.
Background
A photocoupler (optical coupler, abbreviated as OC) is also called a photoisolator or a photocoupler, and is called an optocoupler for short. The device is a device which takes light as a medium to transmit electric signals, and a light emitter (an infrared light emitting diode) and a light receiver (a phototriode) are usually packaged in the same tube shell. When the input end is electrified, the light-emitting diode emits light, and the light receiver receives the light, then a photocurrent is generated and flows out from the output end, thereby realizing 'electricity-light-electricity' conversion. The photoelectric coupler uses light as medium to couple the input end signal to the output end, and has the advantages of small volume, long service life, no contact, strong anti-interference capability, insulation between the output and the input, unidirectional signal transmission and the like, so that the photoelectric coupler is widely applied to digital circuits.
The main advantages of the photoelectric coupler are: the signal one-way transmission, input and output have realized electrical isolation completely, and output signal does not have the influence to the input, and the interference killing feature is strong, job stabilization, contactless, long service life, transmission efficiency is high. Photocouplers are now widely used in electrical insulation, level conversion, inter-stage coupling, drive circuits, switching circuits, choppers, multivibrators, signal isolation, inter-stage isolation, pulse amplification circuits, digital instruments, long-distance signal transmission, pulse amplification, Solid State Relays (SSRs), instrumentation, communication equipment, and microcomputer interfaces.
The high-voltage alternating-current voltage detection circuit is an optimal technical scheme for detecting the input signal of the high-voltage end by utilizing the electrical isolation characteristic of the photoelectric coupler, and the scheme can realize the mutual isolation of the high-voltage end and the low-voltage end and avoid the interference of the high-voltage end to the low-voltage end.
However, in the existing application, the photocoupler is in a continuous working state in the whole variation cycle of the alternating voltage, and the long-time working causes the temperature of the light emitter in the photocoupler to rise, thereby causing the on-state voltage on the PN junction of the internal light emitting diode to change, and causing the temperature drift phenomenon, that is, the on-state voltage to decrease. The current detection precision that adopts photoelectric coupler receives temperature variation's influence owing to above reason, leads to the technical problem that the detected signal precision of photoelectric coupler output reduces.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide an alternating voltage detection circuit for inhibiting temperature drift of a photoelectric coupler, and aims to solve the technical problem that detection precision is reduced due to temperature drift when the alternating voltage is detected by the photoelectric coupler in the prior art.
The alternating voltage detection circuit for inhibiting the temperature drift of the photoelectric coupler is used for detecting the alternating voltage to judge the state of the alternating voltage, and comprises an alternating current input end for inputting the alternating voltage and the photoelectric coupler, wherein the photoelectric coupler comprises an input positive electrode, an input negative electrode and an output end.
Wherein, alternating voltage detection circuit still includes:
one end of the voltage division unit is electrically connected to the alternating current input end;
one end of the clamping unit is electrically connected to the alternating current input end and the input anode, and the other end of the clamping unit is grounded;
the controlled adjusting unit is provided with a controlled end, a positive electrode input end and a negative electrode output end, the positive electrode input end is electrically connected with the other end of the voltage dividing unit, the negative electrode output end is electrically connected to the input negative electrode, and the controlled end is electrically connected to the voltage dividing unit;
the photoelectric coupler periodically outputs pulse detection voltage from the output end under the control of the controlled adjusting unit, so that the photoelectric coupler works in a linear interval and avoids long-time work.
Wherein the clamping unit outputs a first voltage; the voltage dividing unit makes the controlled adjusting unit turn on for a time T1 of a positive half cycle of the alternating voltage and makes the controlled adjusting unit turn off for a time T2 of the positive half cycle of the alternating voltage and a negative half cycle of the alternating voltage; the controlled regulating unit outputs a second voltage; the first voltage is greater than the second voltage in the time T1, and the difference between the first voltage and the second voltage is greater than the light-emitting conduction voltage of the photoelectric coupler, so that the photoelectric coupler is in a signal output state only in the time T1 of a positive half cycle, and outputs the detection voltage.
The alternating current voltage detection circuit further comprises a current limiting unit, wherein the current limiting unit is electrically connected between the alternating current input end and the clamping unit and used for limiting current, so that the clamping unit and the photoelectric coupler can work normally.
The alternating current voltage detection circuit further comprises a direct current power supply end, the photoelectric coupler further comprises an input power supply end, and the direct current power supply end is electrically connected with the photoelectric coupler through the input power supply end; and the direct current power supply end is used for providing working voltage for the output end of the photoelectric coupler.
The voltage dividing unit comprises a first resistor and a second resistor, one end of the first resistor is electrically connected with the alternating current input end, the other end of the first resistor is electrically connected with one end of the second resistor, and the other end of the second resistor is grounded.
The controlled adjusting unit comprises an adjustable voltage stabilizer, the adjustable voltage stabilizer comprises a controlled end, an anode input end and a cathode output end, wherein the controlled end is electrically connected to the first resistor and the second resistor, the anode input end is electrically connected with the other end of the second resistor, and the cathode output end is electrically connected with the input cathode of the photoelectric coupler.
And a controlled end voltage is arranged between the first resistor and the second resistor, and the controlled end voltage is greater than the minimum conducting voltage required by the adjustable voltage regulator to conduct in the time of T1 positive half cycle of the alternating current voltage.
Wherein the first voltage is positive and constant during a time T1 when the alternating voltage is in a positive half cycle.
The clamping unit comprises a voltage stabilizing tube, the voltage stabilizing tube comprises an input positive end and an output negative end, the input positive end is grounded, and the output negative end is electrically connected to the alternating current input end.
The current limiting unit is a third resistor, the clamping unit comprises a voltage stabilizing tube, the voltage stabilizing tube comprises an input positive end and an output negative end, one end of the third resistor is electrically connected with the alternating current input end, the other end of the third resistor is electrically connected with the output negative end, and the input positive end is grounded.
According to the alternating current detection circuit disclosed by the utility model, the photoelectric coupler can be conducted to work within the time of the positive half period T1 of the alternating current voltage, and the detection voltage is output; the photoelectric coupler is cut off in the time of the positive half period T2 and the whole negative half period of the alternating voltage, and outputs the detection voltage of zero. In the whole change process of the alternating voltage, the photoelectric coupler is non-conductive in most of the period time, conductive in a small part of the period time, and output detection voltage is a pulse signal, so that the technical problem that in the prior art, the photoelectric coupler is always in a working conduction state, so that the internal temperature is increased, and the detection precision is reduced due to the fact that the temperature drift of the photoelectric coupler can be restrained is solved.
On the other hand, the alternating current detection circuit compares the alternating voltage thereof by using the controlled regulating unit, so that the alternating voltage outputs on-off switching signals to control the on-off of the photoelectric coupler, the problem that the detection precision of the electric parameter of the photoelectric coupler is reduced due to the change of the temperature of the photoelectric coupler is solved, the photoelectric coupler is prevented from working in a linear region, and the temperature drift of the photoelectric coupler is inhibited, thereby improving the alternating current detection precision.
Drawings
FIG. 1 is a schematic block diagram of the present invention;
FIG. 2 is a block diagram of another embodiment of the present invention;
FIG. 3 is a schematic diagram of the circuit configuration of the present invention;
fig. 4 is a graph of voltage waveforms in the circuit of fig. 3.
Reference numbers:
100. an alternating voltage detection circuit; 10. an alternating current input end; 20. a photoelectric coupler; 21. an output end; 30. a voltage dividing unit; r1, first resistor; r2, second resistance; d1, a voltage stabilizing tube; d2, an adjustable voltage regulator; 40. a clamping unit; 50. a controlled regulating unit; 60. a current limiting unit; r3, third resistor; 70. a direct current power supply terminal; v1, first voltage; v2, second voltage; v3, controlled voltage; vx, minimum on-voltage; v0, light emission on voltage.
Detailed Description
The utility model will be further elucidated and described with reference to a specific embodiment and the drawings of the specification:
referring to fig. 1 to 3, the present invention discloses an ac voltage detection circuit 100 for suppressing temperature drift of a photocoupler 20, wherein the ac voltage detection circuit 100 is used for detecting an ac voltage to determine a state of the ac voltage.
The ac voltage detection circuit 100 includes an ac input terminal 10 to which the ac voltage is input, a photocoupler 20, and the photocoupler 20 includes an input positive electrode and an input negative electrode, and an output terminal 21.
Wherein, the alternating voltage detection circuit 100 further includes: a voltage dividing unit 30, a clamping unit 40, and a controlled adjusting unit 50.
Specifically, one end of the voltage dividing unit 30 is electrically connected to the ac input terminal 10; one end of the clamping unit 40 is electrically connected to the ac input terminal 10 and the input positive electrode, and the other end of the clamping unit 40 is grounded; the controlled adjusting unit 50 has a controlled end, a positive input end and a negative output end, the positive input end is electrically connected with the other end of the voltage dividing unit 30, the positive output end is electrically connected to the input negative electrode, and the controlled end is electrically connected to the voltage dividing unit 30; the photo coupler 20 periodically outputs a pulse detection voltage from the output terminal under the control of the controlled adjustment unit 40, so that the photo coupler 20 is prevented from operating for a long time and operating in a linear section.
Wherein the clamping unit 40 makes the input positive pole obtain a first voltage V1 within a positive half cycle T1 of the alternating voltage; the first voltage V1 is applied to the input positive electrode of the photocoupler 20, a light emitter is provided inside the photocoupler 20, and the first voltage V1 is the positive input voltage of the light emitter (light emitting diode) in the photocoupler 20.
The voltage dividing unit 30 makes the controlled regulating unit 50 conduct for a time T1 of a positive half cycle of the ac voltage, outputs a second voltage V2, and makes the controlled regulating unit 50 turn off for a time T2 of a positive half cycle and a negative half cycle of the ac voltage, wherein the positive half cycle is T1+ T2.
The first voltage V1 is greater than the second voltage V2, and the difference between the first voltage V1 and the second voltage V2 is greater than the light emission turn-on voltage V0 of the photo-coupler 20, so that the photo-coupler 20 is in a signal output state only during the positive half period T1.
In this embodiment, the voltage drop of the positive electrode and the negative electrode of the light emitter in the on state is V0, and the light emitting on voltage required for the light emitting on of the photocoupler 20 is V0, that is, when the voltage between the positive electrode and the negative electrode of the light emitter is greater than the light emitting on voltage V0, the light emitter can only emit light.
When the alternating-current voltage is within a time of a positive half cycle T1, the first voltage V1 is positive and is a constant value, at this time, the clamping unit 40 is equivalent to a constant-voltage source, and the first voltage V1 is loaded on the input positive electrode of the optoelectronic coupler 20 to provide a positive-electrode input voltage for the light emitter; the voltage dividing unit 30 outputs a controlled voltage V3 within a time of the positive half-cycle T1 of the ac voltage, the controlled voltage V3 is greater than the minimum turn-on voltage Vx of the controlled adjusting unit 50, and the controlled voltage V3 is configured to control the controlled adjusting unit 50 to turn on, so that the controlled adjusting unit 50 turns on within a time of the positive half-cycle T1 of the ac voltage, and outputs a second voltage V2. The minimum on-state voltage Vx is the minimum voltage required when the positive input end and the negative input end are conducted in the positive direction on the controlled end.
At this time, the second voltage V2 is output from the negative output terminal of the controlled regulating unit 50 to the input negative terminal of the photocoupler 20. In this case, the input positive electrode of the light emitter of the photocoupler 20 has a first voltage V1, the input negative electrode of the light emitter of the photocoupler 20 has a second voltage V2, and when the difference between the first voltage V1 and the second voltage V2 is greater than the light emission on voltage V0 of the photocoupler 20, the light emitter is turned on to emit light, so that the detection voltage Vout is stably output at the output terminal 21 of the photocoupler 20, and the detection voltage Vout is positive.
In another case, when the ac voltage is within the positive half period T2, the voltage dividing unit 30 outputs the controlled voltage V3 during the time T2 of the positive half period of the ac voltage, and the controlled voltage V3 is smaller than the minimum conduction voltage Vx of the controlled adjusting unit 50, the controlled adjusting unit 50 is non-conductive during the time T2 of the positive half period of the ac voltage, the output terminal of the controlled adjusting unit 50 exhibits a high resistance state, no effective current loop is formed between the negative input terminal of the photocoupler 20 and the controlled adjusting unit 50, and the light emitter is non-conductive and does not emit light, so that the amplitude of the detected voltage output at the output terminal of the photocoupler 20 is also zero.
When the alternating voltage is in a negative half period, the first voltage V1 is negative, and the first voltage V1 is loaded on the input positive pole of the photoelectric coupler 20; the voltage dividing unit 30 outputs the controlled voltage V3 in the negative half cycle of the ac voltage, the controlled voltage V3 is negative, the controlled voltage V3 is difficult to control the controlled regulating unit 50 to conduct, and the negative output terminal of the controlled regulating unit 50 exhibits a high resistance state. At this time, the input positive electrode of the light emitter of the photocoupler 20 is a first voltage V1, the input negative electrode of the light emitter of the photocoupler 20 is a second voltage V2, the voltage drop direction of the first voltage V1 and the second voltage V2 is opposite to the polarity of the input positive electrode and the input negative electrode of the photocoupler 20, the light emitter is not conducted and does not emit light, and thus the amplitude of the output detection voltage at the output end of the photocoupler 20 is zero.
In the present embodiment, the photo coupler 20 is capable of conducting operation during a positive half cycle T1 of the ac voltage, and outputting a detection voltage Vout; the photo-coupler 20 is turned off during the positive half period T2 and the entire negative half period of the ac voltage, and outputs the detection voltage Vout of zero. In the whole change process of the alternating voltage, the photoelectric coupler 20 is not conducted in most of the time period, is conducted in a small part of the time period, and outputs the detection voltage as a pulse signal, so that the technical problem that in the prior art, the internal temperature is increased due to the fact that the photoelectric coupler 20 is always in a working conduction state, and the detection precision is reduced is solved.
On the other hand, the ac detection circuit 100 compares the ac voltage with the controlled adjustment unit 50, so that the controlled adjustment unit outputs on and off switching signals to control the on and off of the photoelectric coupler 20, thereby overcoming the problem of the detection accuracy reduction caused by the temperature change of the electric parameter of the photoelectric coupler 20, avoiding the photoelectric coupler 20 from working in the linear region, and inhibiting the temperature drift of the photoelectric coupler 20 to improve the ac voltage detection accuracy.
In a specific embodiment of the present invention, the waveform of the detection voltage Vout output by the ac voltage detection circuit 100 can be detected to determine the state of the ac voltage Vin input from the ac input terminal 10, for example: the magnitude of the detection voltage Vout and the number of pulses in a plurality of alternating voltage periods are detected to determine whether the detection voltage Vout exists. When the amplitude of the detected voltage Vout in a plurality of alternating voltage periods is greater than a preset value and is greater than a preset value in the set N alternating voltage periods, it may be determined that the alternating voltage Vin is present and normal, otherwise it is determined that the alternating voltage Vin is in an abnormal state.
Of course, the cycle timing of the ac voltage Vin may also be determined according to the detected voltage Vout, for example: the time sequence state of the current alternating voltage Vin can be judged by detecting the period of the detection voltage Vout and the positions of the rising edge and the falling edge of the pulse; the magnitude of the ac voltage may also be determined according to the detected voltage Vout, for example: after the voltage of the voltage dividing unit 30 is divided, the controlled voltage V3 output by the voltage dividing unit 30 changes in proportion to the ac voltage Vin, as the amplitude of the ac voltage Vin increases, the on-time of the controlled adjusting unit 50 increases, the duty ratio of the detected voltage Vout increases, and after the duty ratio of the detected voltage Vout is calculated, the amplitude of the ac voltage Vin can be calculated in a reverse direction.
In addition, the detection voltage Vout is an output mode of the pulse signal, and the detection voltage Vout can be further applied to a digital signal processing circuit, so that more application scenes can be obtained.
In the utility model, the detection voltage Vout can be connected to a control module for controlling an external relay, the control module is used for controlling the on-off of the relay, and the control module controls the relay to be closed in advance and to be switched on in a delayed manner according to the periodic change of the detection voltage Vout, so that the relay is protected, the relay is prevented from being impacted by the surge of a rear end load when the position of the voltage zero point is changed, and the damage of the relay can be effectively avoided. For example, the control module synchronously determines the zero point position t0 moment of the alternating current input voltage according to the period of the periodic Vout pulse signal, and the control circuit closes and keeps the relay at the t0 moment of the alternating current input voltage by t time; the control circuit delays t0 time of the alternating current input voltage for t time, controls the relay to keep a closed state in the delay process, and controls the relay to be conducted after the delay is finished. In the mode, the relay can be ensured to be in a closed state before and after the zero position of the input voltage with periodic change, so that the relay cannot be damaged by large surge voltage from the rear end of the relay.
Further, the ac voltage detecting circuit 100 further includes a current limiting unit 60, and the current limiting unit 60 is electrically connected between the ac input terminal 10 and the clamping unit 40 and is used for limiting a current, so as to ensure that the clamping unit 40 and the photocoupler 20 operate normally, wherein the current limiting unit 60 is a resistor.
In the present embodiment, especially when the ac voltage is in the negative half cycle, the voltage dividing unit 30 outputs the controlled voltage V3 in the negative half cycle of the ac voltage, the controlled voltage V3 is negative, it is difficult to control the controlled adjusting unit 50 to conduct, the output end of the controlled adjusting unit 50 exhibits a high resistance state, and the first voltage V1 on the clamping unit 40 is the negative voltage of the ac voltage. At this time, the negative voltage is applied between the ac input terminal 10 and the ground terminal through the clamping unit 40 and the current limiting unit 60, and the current limiting unit 60 sets a resistance impedance to reduce the current flowing through the clamping unit, so as to pull down the voltage between the input positive terminal of the photocoupler 20 and the positive input terminal of the controlled adjusting unit 50, thereby achieving the purpose of protecting the photocoupler 20 and the controlled adjusting unit 50. Meanwhile, the positive input end and the negative output end of the clamping unit 40 are loaded with positive voltages, which are equivalent to common diodes, so that the first voltage V1 on the clamping unit 40 is a negative voltage, and the value of the first voltage V1 is smaller than the reverse voltages of the photocoupler 20 and the controlled adjusting unit 50, and the voltage between the input positive end of the photocoupler 20 and the positive input end of the controlled adjusting unit 50 is clamped within a positive conduction voltage drop of the clamping unit 40, thereby further protecting the photocoupler 20 and the controlled adjusting unit 50 from breakdown.
Further, the alternating current voltage detection circuit 100 further includes a direct current power supply end 70, the photoelectric coupler 20 further includes an input power supply end, the direct current power supply end 70 is electrically connected to the photoelectric coupler 20 through the input power supply end, and the direct current power supply end 70 is configured to provide a working voltage to the output end of the photoelectric coupler 20.
Referring to fig. 3 and 4, in an embodiment of the utility model, the voltage dividing unit 30 includes a first resistor R1 and a second resistor R2, one end of the first resistor R1 is electrically connected to the ac input terminal 10, the other end of the first resistor R1 is electrically connected to one end of the second resistor R2, and the other end of the second resistor R2 is grounded. The voltage between the first resistor R1 and the second resistor R2 is controlled voltage V3, the controlled voltage V3 and the alternating current voltage change synchronously, and the amplitude is smaller than the alternating current voltage after voltage division.
Controlled regulating unit 50 includes adjustable regulator D2, adjustable regulator D2 includes controlled end, positive input end and negative pole output, wherein, controlled end electric connection to first resistance R1 with between the second resistance R2, the positive input end with second resistance R2 other end electric connection, the negative pole output with optoelectronic coupler 20 inputs negative pole electric connection. In this embodiment, the controlled terminal voltage V3 is greater than the turn-on voltage of the adjustable voltage regulator D2 during the positive half-cycle T1 of the ac voltage. Specifically, the controlled end voltage V3 is the same as the controlled voltage V3, wherein the minimum voltage required by the controlled end when the adjustable voltage regulator D2 is turned on is the minimum on-voltage Vx, and the minimum on-voltage Vx is between a voltage zero value and the maximum positive value of the controlled voltage V3, so that the adjustable voltage regulator D2 is partially turned on in the positive half cycle T1 of the ac voltage, and further the photocoupler 20 operates in the positive half cycle T1 of the ac voltage to output the detection voltage Vout.
In other embodiments of the present invention, the controlled adjusting unit 50 may also be a combination of an adjustable regulator D2 and any one of a three-terminal adjustable regulator, a triode, a MOS transistor, a regulator, and an operational amplifier.
The clamping unit 40 includes a voltage regulator D1, and the voltage regulator D1 includes an input positive terminal and an output negative terminal, the input positive terminal is grounded, and the output negative terminal is electrically connected to the ac input terminal 10. In this circuit, the zener diode D1 provides the input voltage to the positive input terminal of the optocoupler 20 during the positive half cycle of the ac voltage.
When the alternating voltage is within the positive half period T1 and the controlled voltage V3 is greater than the minimum on-state voltage Vx of the adjustable regulator D2, the output negative terminal of the zener D1 outputs a positive constant voltage, i.e., the first voltage V1, and the adjustable regulator D2 is turned on, and outputs the second voltage V2 to the input negative terminal of the photoelectric coupler 20, and the voltage between the input positive terminal and the input negative terminal of the photoelectric coupler 20 is greater than the light-emitting on-state voltage V0, and the photoelectric coupler 20 operates to output a detection voltage.
When the alternating-current voltage is within a positive half period of T1 and the controlled voltage V3 is smaller than the minimum on-voltage Vx of the adjustable voltage regulator D2, the output negative terminal of the voltage regulator D1 outputs a positive constant voltage, i.e., the first voltage V1, the adjustable voltage regulator D2 is turned off, the input negative terminal of the photoelectric coupler 20 is in a high impedance state, the photoelectric coupler 20 does not operate, and the photoelectric coupler 20 does not output a detection voltage.
When the alternating voltage is in a negative half period, the output negative end of the voltage regulator tube D1 outputs a small negative constant voltage to achieve the purpose of clamping, the adjustable voltage regulator D2 is insufficient to conduct the adjustable voltage regulator D2 because the controlled voltage V3 is the negative voltage, the input negative end of the photoelectric coupler 20 is in a high-impedance state, the photoelectric coupler 20 does not work, and the photoelectric coupler 20 does not output detection voltage. Meanwhile, the current limiting unit 60 adopts a third resistor R3 to achieve the purpose of current limiting, so as to protect the photocoupler 20 and the adjustable voltage regulator D2.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (10)
1. The utility model provides an alternating voltage detection circuitry of temperature drift of suppression optoelectronic coupler for detect alternating voltage in order to judge alternating voltage's state, alternating voltage detection circuitry is including the input alternating voltage's alternating current input end and optoelectronic coupler, optoelectronic coupler is including input positive pole and input negative pole to and output, its characterized in that, alternating voltage detection circuitry still includes:
one end of the voltage division unit is electrically connected to the alternating current input end;
one end of the clamping unit is electrically connected to the alternating current input end and the input anode, and the other end of the clamping unit is grounded;
the controlled adjusting unit is provided with a controlled end, a positive electrode input end and a negative electrode output end, the positive electrode input end is electrically connected with the other end of the voltage dividing unit, the negative electrode output end is electrically connected to the input negative electrode, and the controlled end is electrically connected to the voltage dividing unit;
the photoelectric coupler periodically outputs pulse detection voltage from the output end under the control of the controlled regulating unit, so that the photoelectric coupler is prevented from working for a long time and working in a linear interval.
2. The alternating current voltage detection circuit that suppresses temperature drift of a photocoupler as described in claim 1, wherein said clamping unit outputs a first voltage; the voltage dividing unit makes the controlled adjusting unit turn on during a time T1 of a positive half cycle of the alternating voltage, and makes the controlled adjusting unit turn off during a time T2 of the positive half cycle of the alternating voltage and during a negative half cycle of the alternating voltage; the controlled regulating unit outputs a second voltage; the first voltage is greater than the second voltage within a time T1, and a difference between the first voltage and the second voltage is greater than a light-emitting conduction voltage of the photoelectric coupler, so that the photoelectric coupler is in a signal output state only within a time T1 of a positive half cycle and outputs the detection voltage.
3. The alternating current voltage detection circuit for suppressing temperature drift of a photocoupler according to claim 1, further comprising a current limiting unit electrically connected between said alternating current input terminal and said clamping unit for limiting current, thereby ensuring normal operation of said clamping unit and said photocoupler.
4. The alternating current voltage detection circuit for suppressing temperature drift of a photocoupler according to claim 1 or 2, wherein said alternating current voltage detection circuit further comprises a direct current power supply terminal, said photocoupler further comprises an input power supply terminal, said direct current power supply terminal being electrically connected to said photocoupler through said input power supply terminal; and the direct current power supply end is used for providing working voltage for the output end of the photoelectric coupler.
5. The alternating current voltage detection circuit for suppressing temperature drift of a photocoupler according to claim 2, wherein said voltage dividing unit includes a first resistor and a second resistor, one end of said first resistor is electrically connected to said alternating current input terminal, the other end of said first resistor is electrically connected to one end of said second resistor, and the other end of said second resistor is grounded.
6. The ac voltage detecting circuit for suppressing temperature drift of a photocoupler according to claim 5, wherein said controlled adjusting unit comprises an adjustable regulator, said adjustable regulator comprising said controlled terminal, said positive input terminal and said negative output terminal, wherein said controlled terminal is electrically connected between said first resistor and said second resistor, said positive input terminal is electrically connected to the other end of said second resistor, and said negative output terminal is electrically connected to the negative input terminal of said photocoupler.
7. The ac voltage detecting circuit for suppressing temperature drift of an opto-coupler according to claim 6, wherein said first resistor and said second resistor have a controlled terminal voltage therebetween, said controlled terminal voltage being greater than a minimum turn-on voltage required for said adjustable voltage regulator to turn on during a time T1 when said ac voltage is in a positive half cycle.
8. The alternating current voltage detection circuit that suppresses temperature drift of a photocoupler as set forth in claim 7, wherein said first voltage is positive and constant during a time T1 when said alternating current voltage is in a positive half cycle.
9. The alternating current voltage detection circuit for suppressing temperature drift of a photocoupler as claimed in claim 1, wherein said clamping unit includes a voltage regulator tube, said voltage regulator tube including an input positive terminal and an output negative terminal, said input positive terminal being grounded, said output negative terminal being electrically connected to said alternating current input terminal.
10. The alternating current voltage detection circuit for suppressing temperature drift of a photocoupler as claimed in claim 3, wherein said current limiting unit is a third resistor, said clamping unit includes a voltage regulator tube, said voltage regulator tube includes an input positive terminal and an output negative terminal, one end of said third resistor is electrically connected to said alternating current input terminal, the other end of said third resistor is electrically connected to said output negative terminal, and said input positive terminal is grounded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220140885.5U CN217034092U (en) | 2022-01-19 | 2022-01-19 | Alternating voltage detection circuit for inhibiting temperature drift of photoelectric coupler |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220140885.5U CN217034092U (en) | 2022-01-19 | 2022-01-19 | Alternating voltage detection circuit for inhibiting temperature drift of photoelectric coupler |
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| CN217034092U true CN217034092U (en) | 2022-07-22 |
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| CN202220140885.5U Active CN217034092U (en) | 2022-01-19 | 2022-01-19 | Alternating voltage detection circuit for inhibiting temperature drift of photoelectric coupler |
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- 2022-01-19 CN CN202220140885.5U patent/CN217034092U/en active Active
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